Projection systems are usually produced using discharge lamps which have elevated power consumption and a short service life. LED projectors with a significantly longer service life and more efficient mode of operation are also known. Drawbacks of LED projectors are, however, their lower light output due to the light sources they use and losses in the optical system. In conventional projection systems, light emerging from the light source is mixed, homogenized and broken down by a color wheel into the colors red, green and blue. The light of the individual colors is projected onto the image-generating element. Typical image generators are an arrangement of LCDs (liquid crystal displays), LCoS (Liquid Crystal on Silicon) or DLP (Digital Light Processing) with an arrangement of small tiltable mirrors. In polarization-based systems with LCDs or LCoS, only one polarization direction is usable. In systems with DLP, the images are sequentially superimposed such that each light source of a particular color is only switched on with interruptions. In this case too, the light output from the light source is thus not fully utilized.
DE 10 2008 013 030 and DE 10 2008 014 094, for example, describe the basic principles of color mixing and contacting of layer stacks of substrateless diodes. DE 10 2008 008 599, DE 10 2008 006 757 and DE 10 2007 062 042 describe contacting methods for substrateless diodes on or between dielectric interlayers.
DE 199 25 318 C1 describes a color image projector with time-controlled LED light sources. WO 03/056876 A2 describes an illumination system with planar multilayer arrangements of LED light sources. US 2008/0211413 A1 describes a display device produced from LEDs. DE 100 63 200 A1 describes a method and a device with LCD reflective modulators. EP 1 609 835 A1 describes a potting compound for LEDs.
It could therefore be helpful to provide a projection system with a long service life and elevated efficiency despite having a low structural height.